System for controlling the operation of modules using information transmitted from a control device via a data bus, a trigger device and a test circuit

• US 20030225461A1
• Filed: 06/13/2002
• Published: 12/04/2003
• Est. Priority Date: 12/14/1999
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Schmidt, Claus
• Granted Patent: US 6,892,121 B2
• Time in Patent Office: Days
• US Class Current: 700/1
• CPC Class Codes: B60R 2021/01027 Safing sensors
• CPC Class Codes: B60R 21/017 including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves
• CPC Class Codes: H04L 12/40013 Details regarding a bus controller
• CPC Class Codes: H04L 12/40032 Details regarding a bus interface enhancer
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle

Abstract

In a data communication system, data is transmitted from a control device (2) to a communication interface (6) and from there via a communication bus (8) to additional communication interfaces (12) of trigger devices (9, 10). The communication interface (6) on the control device side has inputs, to which signals from said control device (2) and a disarming switch (26) can be assigned. The disarming switch can be circumvented by a bypass switch (34) which is controlled by the control device. The state of the signal at the inputs of the communication interface on the control device side (6) is transmitted to corresponding outputs of the communication interfaces (12) of the trigger devices. A trigger device has a safety unit which is used to test at least one trigger unit, when the state of the signal of the outputs authorises such a test and the trigger voltage source is not yet charged with the full trigger voltage. In said state, the safety unit also blocks triggering as soon as the trigger voltage has been reached. The inventive system ensures a high degree of functional safety and flexibility.

Claims

1. A system for controlling the operation of modules by transmitting information from a control device via a databus, in particular for controlling the operation of firing devices of a vehicle occupant protection apparatus in a motor vehicle, containing a communications interface (6) which is connected to the control device (2) via a data line (4) and has an input (32), which communications interface converts data transmitted by the control module into code words which are transmitted via the communications bus (8) and which contain information relating to the data and the signal state of the input (32), characterized in that the communications interface (6) which is connected to the control device (2) has a plurality of inputs (32, 42, 48) to which signals can be applied, and in that the communications bus (8) is connected to the modules (18, 20) via a module-end communications interface (12) which has a plurality of outputs (32₁, 42₁, 48₁) to which signals can be applied, the signal state of the inputs being transmitted to the outputs via the communications bus (8) in such a way that there is a predetermined relationship between the signal states of the inputs and outputs, as a result of which functions of the modules (18, 29) can be disabled and enabled by means of the signal states of the inputs.

2. The system as claimed in claim 1, characterized in that the communications interface (6) which is connected to the control device (2) has a safing input (32) which is connected to a safing switch (26) and a control input (42) which is connected to a control output (46), to which a control signal can be applied, of the control device (2), and in that the communications bus (8) is connected to the modules (18, 20) via a module-end communications interface (12) which has a safing output (32₁) and a control output (48₁), the signal state of the safing input or of the control input being available at the safing output or the control output in order to disable or enable functions of the modules (18, 20).

3. The system as claimed in claim 1 or 2, characterized in that the modules can be addressed selectively by means of a code.

6. The system as claimed in claim 5 and one of claims 1 to 3 for a vehicle occupant protection system of a motor vehicle, characterized in that safety devices (18) which trigger when there is a front-end impact can be triggered only when the safing switch (26) is closed and safety devices (20) which trigger when there is a side impact can also trigger when the safing switch is open.

7. The system as claimed in claim 6, characterized in that when a test signal is present the triggering capability of the safety devices (18) which trigger when there is a front-end impact is disabled.

10. The system as claimed in one of claims 1 to 9, characterized in that the control-device-end communications interface (6) transmits the signal state of its inputs to the control device (2) .

11. A firing device for connection to the communications bus of a system as claimed in claim 3 for a vehicle occupant protection apparatus in a motor vehicle, characterized by the communications interface which can be connected to the communications bus (8) and has a safing output (32₁), the control output (48₁), a code signal output with a firing signal output, a switching device (50) which has a safing switch (61) which can be activated by the safing output (32₁), a control switch (59) which can be activated by control output (42₁), a code input (54) with a firing input, a firing-device-specific code signal present at the coding input determining which of the switches is activated, and a firing signal leading to firing of a firing unit when the safing switch is activated and a safing signal is present and/or control switch is activated and/or a control signal is present, a safety circuit (62) with an AND element (64) whose inputs are connected to the test output (42₁) and to the firing voltage source (58) and whose output is connected to a safety switch (66) which connects the safing output to ground if a test signal is applied to the test output and the firing voltage source has a voltage which is not sufficient to fire the firing unit.

13. The system as claimed in claim 11, characterized in that a monitoring device (68) for the safety switch (66) is provided

4. A system for controlling the operation of modules by transmitting information from a control device via a databus, in particular for controlling the operation of firing devices of a vehicle occupant protection apparatus in a motor vehicle, containing a communications interface (6) which is connected to the control device (2) via a data line (4) and has a safing input (32) connected to a safing switch (26), which communications interface converts data transmitted by the control module into code words which are transmitted via the communications bus (8) and which contain information relating to the data and the signal state of the safing input, characterized in that the control device (2) has a test output (40) to which a test signal can be applied from said control device (2) and which is connected to a further input (42, 48) of the communications interface (6), and in that a bypass switch (34) is provided parallel to the safing switch (26) in such a way that when the test signal generated by the control device is present a signal state corresponding to the closed safing switch is present at the safing input (32) irrespective of the switch state of the safing switch, and in that the communications bus (8) is connected to the modules (12, 20) via a module-end communications interface (12) which has a safing output (32₁) and at least one further output (42₁, 48₁ ), the signal state of the safing input or of the further input being available at the safing output or further output in order to disable or enable functions of the modules.

5. The system as claimed in claim 4, characterized in that the test output (40) of the control device (2) is directly connected to a test input (42) of the communications interface (6), and the further output of the module-end communications interface (12) is formed by a test output (42₁).

8. The system as claimed in claim 4, characterized in that the control input (48) is connected to the test output (40) via a switching device (74) in such a way that when there is a test signal present a signal state which corresponds to the presence of a control signal is present at the control input.

9. The system as claimed in claim 8 for a vehicle occupant protection system in a motor vehicle, characterized by the following relationship between the signal states at the inputs of the control-device-end communications interface and the possibility of enabling or disabling functions:

12. A firing device for connection to the communications bus of a system as claimed in claim 5 for a vehicle occupant protection device in a motor vehicle, characterized by the communications interface which can be connected to the communications bus (8) and has the safing output (32₁), the test output, safing switch (61) which can be activated by the safing output (32₁) and which connects a firing voltage source (53) to a firing unit (62) when there is a signal at the safing output and a firing signal is present, and a safety circuit (63) with an AND element (64) whose inputs are connected to the test output (42₁) and to the firing voltage source (58) and whose output (32₁) is connected to a safety switch (66) which connects the safing output to ground if a test signal is applied to the test output and the firing voltage source has a voltage which is not sufficient to fire the firing unit.

14. A safety circuit for a firing device of a vehicle occupant protection system, containing an input (32₁) to which a signal can be applied and a test input (42₁) to which a test signal can be applied and an AND element (64) whose inputs are connected to the test output and to a firing voltage source (58) and whose output is connected to a safety switch (66) which connects the input (32₁) to ground if a test signal is applied to the test output (42₁) and the firing voltage source (58) has a voltage which is not sufficient to fire the firing unit.